This proposal is to request the purchase of a scanning-transmission electron microscope. Documentation is presented to detail the need for quantitative instrumentation (scanning-transmission) currently not available in the metropolitan area or in the State of Kansas. Our users are investigating such areas as ion diffusion through epithelium, metal toxicity, neurobiology, reproductive physiology, calcium metabolism and immunology. This type of instrumentation is absolutely necessary to the continued advance in these areas. As detailed in this proposal, our research efforts have a strong interdepartmental thrust and the EM Laboratory serves as a point of focus for much of the structure/function studies coming from the College. The proposed microscope will be coupled with the present institutional KUMC Electron Microscopy Research Center (EMRC). This laboratory has the proven administrative structure to provide investigators at KUMC with access to EM instrumentation as well as technical and training assistance. Consultation is available on a faculty level through the Director and his Advisory Committee. Our present laboratory is fully committed so we are not in a position to assist with the needs of many of our investigators unless a new STEM becomes available. It is clear that the 20 NIH funded investigators included in this proposal will utilize the proposed instrument at least 75% of the time. KUMC has been supportive of our efforts since we began this laboratory. The Institution purchased the present TEM, renovated 1200 sq. ft. of space and provides annual support for 1.7 technicians. They propose to continue this support and in addition, they will provide space, renovation and pay the service contract on the new instrument. This will insure the technical expertise to assist and train our investigators and the continued operation of the new instrument.